1. Field of the Invention
This invention relates to a radio remote control system for a model drive unit such as a model plane or the like, and more particularly to a radio remote control system which is adapted to transmit a transmission code representing a control data from a transmission section including a radio transmitter and receive the signal at a receiving section including a radio receiver mounted on a controlled object such as a model car, a model plane or the like to carry out remote control or variable sections of the controlled object, and which is capable of electrically changing relationships between the control data and the variable sections of the controlled object by simple manual operation.
2. Description of the Prior Art
A transmission section of a conventional radio remote control system is constructed as shown in FIG. 3. In the conventional control system, variable resistors 2 and 3 operatively connected to one control lever 1 on a control panel and a variable resistor 4 operatively connected to another control lever 1' on the control panel are separately arranged corresponding to channels respectively allocated to variable sections of a controlled object. The variable resistors 2, 3 and 4 each are connected at one end thereof to a common power supply V and at the other end thereof to the grounds to form a bleeder. The variable resistors 2, 3 and 4 constitute control voltage generating circuits 2A, 3A and 4A, respectively.
When a controlled object is, for example, a model plane, the variable resistor 2 allocated to a first channel is in charge of control of an aileron (aileron of main wing), the variable resistor 3 for a second channel is in charge of control of an elevator (aileron of horizontal tail) and the variable resistor 4 for a third channel is in charge of control of a throttle.
The two control levers 1 and 1' on the control panel are generally operable in both longitudinal and lateral directions, and the variable resistors 2, 3 and 4 are separately operated corresponding to the operation of the control levers 1 and 1' for every displacement region of the levers.
Sliders 2a, 3a and 4a of the variable resistors 2, 3 and 4 in the control voltage generating circuits 2A, 3A and 4A are connected to input terminals of a multiplexer 5, respectively, which is, in turn, connected at an output terminal thereof to a subsequent analog-digital converter 6. The analog-digital converter 6 is connected at an output terminal thereof through a data bus 6a comprising a plurality of wires and led out therefrom to an input terminal of a parallel-serial conversion circuit 7. The parallel-serial conversion circuit 7 is connected at an output terminal thereof through a pair of data lines 7a to an input terminal of a radio transmitter 8 having a transmitting antenna 8a, a clock pulse oscillating circuit 9, and an address counter 10. The counter 10 is connected at an output terminal thereof to an address terminal of the multiplexer 5 through an address bus 10a comprising a plurality of wires.
In the conventional control system, the operation of the two control levers 1 and 1' in the respective displacement regions for the purpose of control causes the sliders 2a, 3a and 4a of the variable resistors 2, 3 and 4 to be slided so that control voltages E1, E2 and E3 corresponding to the amounts of displacement of the control levers 1 and 1' may be induced across the sliders 2a, 3a and 4a, which are, in turn, supplied to the input terminals of the multiplexer 5, respectively.
Supposing that an address code C4 to the multiplexer 5 designates its first input terminal, the control voltage E1 supplied to the first input terminal of the multiplexer 5 is selected and induced across the output terminal of the multiplexer. The voltage E1 is then supplied to the analogdigital converter 6 where it is converted into a parallel digital code and is supplied in the form of a control voltage code C1 representing the control voltage E1 through the data bus 6a to the parallel-serial conversion circuit 7.
The parallel-serial conversion circuit 7 receiving the parallel control voltage code C1 assembles the code C1 into an ordinal transmission code and converts the transmission code into a serial transmission code C2 of a bit rate defined by a frequency of a clock pulse S1 from the clock pulse oscillating circuit 9. The transmission code C2 thus converted is then transferred through the data lines 7a to the radio transmitter 8 for transmitting the code C2 to a radio receiver mounted on the receiving section (not shown).
The parallel-serial conversion circuit 7 supplies a completion code C3 to the address counter 10 to carry out stepping of the code when it completes transfer of the transmission code C2 corresponding to one channel of the control voltage code C1 derived from the control voltage E1. Then, the address counter 10 supplies an address code C4 representing a subsequent address through an address bus 10a to an address terminal of the multiplexer 5, and the multiplexer 5 selects the control voltage E2 supplied to the second input terminal thereof and supplies it through the output terminal thereof to the analog-digital converter 6.
In this manner, when the transmission code C2 for the first channel representing one control voltage is transmitted, stepping of the address code C4 to the multiplexer 5 is carried out to select a subsequent control voltage, and the transmission code C2 for the second channel representing the control voltage is transmitted. In the same manner, a control data indicated by the amount of displacement of each of the control levers 1 and 1' in its displacement region is subjected to time-sharing for each of the channels allocated to the respective variable sections, and then the receiving section which has received it by means of the radio receiver positionally changes each of the variable sections corresponding to the amount of displacement of each of the control levers 1 and 1' to carry out remote control of the controlled object.
In the conventional control system described above, the control data in the transmission section or allocation of the control voltage for every operation of each of the control levers to each of the channels is fixedly specified depending on a wiring connection in the transmission section and allocation of each of the variable sections to each of the channels in the receiving section is also fixedly specified. However, this construction, when one receiving section is controlled in a manner to fixedly correspond to one transmission section or one controlled object, does not cause significant inconvenience because it is merely required to fixedly make appropriate channel allocation at the time of manufacturing of the transmission section.
In general, channel allocation is differently or separately made depending on a type of a controlled object such as a model plane, a model helicopter, a model car or the like. Also, it is separately made depending on a difference in a custom of control between states. For example, in regard to a model plane, a throttle is allocated to a third lever of a control lever on a right side in Japan, whereas it is allocated to a second channel of a control lever on a left side in Europe.
However, it has been recently desired to correspond a plurality of controlled objects to one transmission section in a manner to replace the objects one by one or commonly use one transmission section and one receiving section irrespective of a difference in a custom of control between states so that such a control system of a high grade may be manufactured at a low cost.
In the conventional control system, a change of channel allocation is highly troublesome, because the change must be carried out by switching between wiring connections in the transmission section.